Text-to-speech system and method

• US 20060041429A1
• Filed: 08/10/2005
• Published: 02/23/2006
• Est. Priority Date: 08/11/2004
• Status: Active Grant

• Current Assignee: Cerence Operating Company (Cerence Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Crepy, Hubert, Amato, Christel, Revelin, Stephane, Waast-Richard, Claire
• Granted Patent: US 7,869,999 B2
• Time in Patent Office: Days
• US Class Current: 704/260
• CPC Class Codes: G10L 13/08 Text analysis or generation of parameters for speech synthesis out of text, e.g. grapheme to phoneme translation, prosody generation or stress or intonation determination

Abstract

A system and method for generating synthetic speech, which operates in a computer implemented Text-To-Speech system. The system comprises at least a speaker database that has been previously created from user recordings, a Front-End system to receive an input text and a Text-To-Speech engine. The Front-End system generates multiple phonetic transcriptions for each word of the input text, and the TTS engine uses a cost function to select which phonetic transcription is the more appropriate for searching the speech segments within the speaker database to be concatenated and synthesized.

Claims

1. A Text-To-Speech system comprising:

means for storing a plurality of speech segments;

means for creating a plurality of phonetic transcriptions for each word of an input text; and

means coupled to the storing means and to the creating means for selecting preferred phonetic transcriptions by operating a cost function on the plurality of speech segments.

2. The system of claim 1, wherein the means for selecting preferred phonetic transcriptions comprises means for computing a cost score for each phonetic transcription of the plurality of phonetic transcriptions and means for sorting the plurality of phonetic transcriptions according to the computed cost scores.

3. The system of claim 1, wherein the means for creating a plurality of phonetic transcriptions comprises rule-based means.

4. The system of claim 1, wherein the means for creating a plurality of phonetic transcriptions comprises statistical means.

5. The system of claim 1, wherein the means for creating a plurality of phonetic transcriptions further comprises means to normalize the input text.

6. The system of claim 1, wherein the means for creating a plurality of phonetic transcriptions further comprises means to generate prosody parameters.

7. The system of claim 6, wherein the prosody parameters are input to the means for selecting the preferred phonetic transcriptions.

8. The system of claim 1, wherein the means for selecting the preferred phonetic transcriptions further comprises means for selecting preferred speech segments associated to the preferred phonetic transcriptions.

9. The system of claim 8, further comprising concatenation means to concatene the preferred speech segments.

10. The system of claim 9, further comprising means coupled to the concatenation means to output synthetic speech from the concatenated speech segments.

11. A method for selecting preferred phonetic transcriptions of an input text in a Text-To-Speech system, the method comprising the steps of:

storing a plurality of speech segments;

creating a plurality of phonetic transcriptions for each word of an input text;

computing a cost score for each phonetic transcription by operating a cost function on the plurality of speech segments; and

sorting the plurality of phonetic transcriptions according to the computed cost scores.

12. The method of claim 11, further comprising the step of normalizing the input text before creating the plurality of phonetic transcriptions.

13. The method of claim 11, further comprising the step of generating prosody parameters after the step of creating a plurality of phonetic transcriptions.

14. The method of claim 11, further comprising the step of selecting preferred speech segments after the step of sorting the plurality of phonetic transcriptions.

15. The method of claim 14, further comprising the step of concatenating the preferred speech segments.

16. The method of claim 15, further comprising the step of outputting synthetic speech after the concatenating step.

17. A machine-readable storage having stored thereon, a computer program having a plurality of code sections, said code sections executable by a machine for causing the machine to perform the steps of:

storing a plurality of speech segments;

creating a plurality of phonetic transcriptions for each word of an input text;

computing a cost score for each phonetic transcription by operating a cost function on the plurality of speech segments; and

sorting the plurality of phonetic transcriptions according to the computed cost scores.

18. The machine-readable storage computer system for generating synthetic speech comprising the step of:

normalizing the input text before creating the plurality of phonetic transcriptions.

19. A computer system for generating synthetic speech comprising:

(a) a speaker database to store speech segments;

(b) a front-end interface to receive an input text made of a plurality of words;

(c) an output interface to audibly output the synthetic speech; and

(d) computer readable program means executable by the computer for performing actions, including;

(i) creating a plurality of phonetic transcriptions for each word the input text;

(ii) computing a cost score for each phonetic transcription by operating a cost function on the plurality of speech segments; and

(iii) sorting the plurality of phonetic transcriptions according to the computed cost scores.

20. The system of claim 19 wherein the computer readable program means is embodied on a program storage device readable by a computer machine.